Fix ancient get_object_address_opf_member bug
The original coding was trying to use a TypeName as a string Value,
which doesn't work; an oversight in my commit
a61fd533. Repair.
Also, make sure we cover the broken case in the relevant test script.
Backpatch to 9.5.
Discussion: https://postgr.es/m/
20170315151829.bhxsvrp75xdxhm3n@alvherre.pgsql